Power amp recs for bi amp - bass

[lostwin]

After a reasonable amount of trial and occasional error testing through several bake offs, I think I am going to go down the route of bi-amping my big Snells.

Mid and treble will be picked up by 300B loveliness or similar, but that is for later - my KT88 amp can do that for now. 

Considering now the amplification for the bass units which have 12” drivers in sealed boxes with a separate crossover (I guess more of a filter ) up to 200hz.

I immediately thought of class D but not sure the impedance is going to be in spec (my valve pre output impedance is c. 5kohm). What would you recommend new or second hand with the following specs?;

- 200w plus 

- input impedance 50k plus

- with output / volume control 

- under £1k
 

 

[MF 1000]

For serious bass grunt Richard I don’t think you can beat my Behringer KM750 

https://www.thomann.de/gb/behringer_km750.htm

you could even use them as monoblocks  as I do for less than £400.  
there is an individual vol control for each channel to help you balance the grunt against your valves.

 

[lostwin]

For serious bass grunt Richard I don’t think you can beat my Behringer KM750 

https://www.thomann.de/gb/behringer_km750.htm

you could even use them as monoblocks  as I do for less than £400.  
there is an individual vol control for each channel to help you balance the grunt against your valves.

I immediately thought of this brand but Input impedance is quoted as 14k ohm, would that be an issue?

 

[hearhere]

I immediately thought of class D but not sure the impedance is going to be in spec (my valve pre output impedance is c. 5kohm). What would you recommend new or second hand with the following specs?;

- 200w plus 

You mention Class D and I think you may be well advised to follow that route.  My own speakers (Avantgarde Duo XDs) have powered subs with twin 12" drivers per channel and built-in Class D amplification.

Although outside your £1K budget, you may find a used one occasionally as this is a newly introduced model – the NAD C298.  It has variable gain by adjusting the rear panel control.  This should probably be preferable to conventional front panel volume control.  It uses the best Class D technology available at present, Purifi's Eigentakt.

https://nadelectronics.com/product/c298-stereo-power-amplifier

You'll see from the back panel that you can feed the C298 with balanced or single-ended signal so this may be a useful feature if your preamp offers both, or there's a single-ended pre-out that could feed your KT88 amp - either could avoid the need for Y interconnects.  There's also a triggers so you don't need to turn it off or on if your preamp has a trigger too.

My own amp is the NAD M33 that features the same amp module but it comes with full preamp, streamer, room correction, etc at a price of £4K - but still a bargain and good enough to justify its use to power £32K speakers.  I chose it over a dozen other amps at prices from £5-8+K

 

[MF 1000]

I immediately thought of this brand but Input impedance is quoted as 14k ohm, would that be an issue?

They work fine on the end of my type 26 DHT preamp ….not sure what it’s requirements are with it being a none off build.  The only negative point is you can hear the cooling fan when no music is playing ….but it’s a minor issue fur me given the performance they give…..750 watt monoblocks for £280 is insane value imho 

 

[lostwin]

You mention Class D and I think you may be well advised to follow that route.  My own speakers (Avantgarde Duo XDs) have powered subs with twin 12" drivers per channel and built-in Class D amplification.

Although outside your £1K budget, you may find a used one occasionally as this is a newly introduced model – the NAD C298.  It has variable gain by adjusting the rear panel control.  This should probably be preferable to conventional front panel volume control.  It uses the best Class D technology available at present, Purifi's Eigentakt.

https://nadelectronics.com/product/c298-stereo-power-amplifier

You'll see from the back panel that you can feed the C298 with balanced or single-ended signal so this may be a useful feature if your preamp offers both, or there's a single-ended pre-out that could feed your KT88 amp - either could avoid the need for Y interconnects.  There's also a triggers so you don't need to turn it off or on if your preamp has a trigger too.

My own amp is the NAD M33 that features the same amp module but it comes with full preamp, streamer, room correction, etc at a price of £4K - but still a bargain and good enough to justify its use to power £32K speakers.  I chose it over a dozen other amps at prices from £5-8+K

Very interesting, thanks. I am somewhat outside my comfort zone with this type of amp hence seeking advice - this looks really interesting and bang on spec

 

[lostwin]

They work fine on the end of my type 26 DHT preamp ….not sure what it’s requirements are with it being a none off build.  The only negative point is you can hear the cooling fan when no music is playing ….but it’s a minor issue fur me given the performance they give…..750 watt monoblocks for £280 is insane value imho 

It’s a very tempting option Keith, at this sort of price you almost can’t lose.

 

[MF 1000]

Well if you use the distance selling regs ‘scam’ you could test drive a pair fir a week and return them if they didn’t suit your setup